Former Defense Minister Shigeru Ishiba won Japan's ruling Liberal Democratic Party (LDP) presidential election on Friday, virtually ensuring that he will become the country's next prime minister.

The 67-year-old lawmaker secured 215 votes in a runoff to win over his female contender, Sanae Takaichi, who received 194 votes.

Although he is relatively popular with the public, Ishiba has had four failed bids to lead the LDP, including a 2012 attempt against his arch-rival Shinzo Abe before prevailing this time against a nationalist.

For a long time, Ishiba alienated party heavyweights with his "outspoken criticism of LDP policies under Abe," said Yu Uchiyama, a politics professor at the University of Tokyo.

But recently he has been "vocal about the need for the LDP to turn over a new leaf when it comes to the funding scandal and other issues," which may have worked in his favor, according to an AFP report. 

CGTN correspondent Chris Gilbert said Ishiba is a strong advocate for strengthening and codifying the status of the Self-Defense Forces. He is a bit more conservative when it comes to pursuit of nuclear energy, Gilbert added. 

He has also proposed creating a government agency in charge of disaster prevention in the earthquake-prone country that is also frequently hit by typhoons and heavy rains.

"My life's work is security, disaster prevention and the revitalization of rural regions," Ishiba said in a recent interview with the Mainichi Shimbun daily, pledging to focus on these issues as prime minister.

As the LDP-led coalition constitutes a majority in both chambers of the parliament in Japan, the new party leader is almost certain to be elected prime minister in the extraordinary Diet session scheduled to be held on October 1, succeeding the incumbent Fumio Kishida.

(With input from agencies)